Updated on 2024/07/18

写真a

 
HIRATA,Koji
 
Organization
Faculty of Engineering Science Professor
Title
Professor
Other name(s)
Kouji Hirata
External link

Degree

  • 博士（工学） ( 2008.3 )

Research Areas

  • Informatics / Information network

Education

  • Osaka University   Faculty of Engineering

    - 2003

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  • Osaka University   Graduate School, Division of Engineering

    2008

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Research History

Professional Memberships

Papers

  • Design of Multi-Armed Bandit-Based Routing for in-Network Caching Reviewed

    Gen Tabei, Yusuke Ito, Tomotaka Kimura, Kouji Hirata

    IEEE Access   11   82584 - 82600   2023.8

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    Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Electrical and Electronics Engineers (IEEE)  

    DOI： 10.1109/access.2023.3301961

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  • Deployment Method with Connectivity for Drone Communication Networks Reviewed

    Hirofumi Osumi, Tomotaka Kimura, Kouji Hirata, Chinthaka Premachandra, Jun Cheng

    Drones   7 ( 6 )   2023.6

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  • Game-theoretic approach to epidemic modeling of countermeasures against future malware evolution Reviewed

    H. Miura, T. Kimura, H. Aman, K. Hirata

    Computer Communications   206   160 - 171   2023.5

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  • Design of multiple routing configurations considering load distribution for network slicing Reviewed

    T. Misugi, H. Miura, K. Hirata, T. Tachibana

    APSIPA Transactions on Signal and Information Processing   vol. 12, no. 2, e9   2023.4

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  • P4-based design of fast failure recovery for software-defined networks Reviewed

    Hideyoshi Miura, Kouji Hirata, Takuji Tachibana

    Computer Networks   216   109274 - 109274   2022.10

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    Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

    DOI： 10.1016/j.comnet.2022.109274

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  • Integrated Design of Edge Computing Systems with Edge Server Placement and Virtual Machine Allocation Reviewed

    Shota Nangu, Ayaka Takeda, Tomotaka Kimura, Kouji Hirata

    IEEJ Transactions on Electronics, Information and Systems   141 ( 12 )   1321 - 1330   2021.12

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    Publishing type：Research paper (scientific journal)   Publisher：Institute of Electrical Engineers of Japan (IEE Japan)  

    DOI： 10.1541/ieejeiss.141.1321

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  • Design of energy‐efficient intermittently connected sensor networks Reviewed

    Tomotaka Kimura, Masahiro Fukuoka, Kouji Hirata, Masahiro Muraguchi

    IEEJ Transactions on Electrical and Electronic Engineering   16 ( 11 )   1500 - 1509   2021.7

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    Publishing type：Research paper (scientific journal)   Publisher：Wiley  

    DOI： 10.1002/tee.23454

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    Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/tee.23454

  • Static routing and spectrum allocation method for design of low-power elastic optical networks with multifiber environments Reviewed

    T. Kudo, T. Kimura, Y. Fukuchi, K. Hirata

    Optical Switching and Networking   2021.5

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  • Deterministic epidemic modeling of future botnet malware with a contact process Reviewed

    H. Miura, T. Kimura, K. Hirata

    IEICE Communications Express   vol. 10, no. 6, pp. 295-300   2021.4

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  • アジアにおける英語による専門教育(EMI)の課題と展望: 日本と台湾での実践から

    奥田 隆一, 山本 英一, 西 平等, 田中 孝憲, 平田 孝志, 林 沁雄, 陳 立剛, 李 淑容, 施 富盛

    関西大学高等教育研究   vol. 12, pp. 99-111   2021.3

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  • Modeling of malware diffusion with the FLIPIT game

    Hideyoshi Miura, Tomotaka Kimura, Kouji Hirata

    2020 IEEE International Conference on Consumer Electronics - Taiwan, ICCE-Taiwan 2020   2020.9

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    Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Institute of Electrical and Electronics Engineers Inc.  

    In this paper, we examine the optimal strategy to control the spread of the infection by applying the FLIPIT game to malware epidemic models. In the FILPIT game for the epidemic models, an attacker and a defender compete for computing resources of hosts. The attacker infects the hosts with malware and abuses their computing resources for illegal attacks. On the other hand, the defender protects the hosts from the attacker by removing vulnerabilities and malware. We calculate the payoff obtained by the FLIPIT game through simulation experiments. Furthermore, based on the best response strategy and the Nash equilibrium derived from the results, we examine the optimal behavior for the attacker and the defender.

    DOI： 10.1109/ICCE-Taiwan49838.2020.9257999

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  • Design of low-power all-optical networks under the constraint of four-wave mixing. Reviewed

    Kouji Hirata, Tomotaka Kimura, Yutaka Fukuchi, Masahiro Muraguchi

    Int. J. Commun. Syst.   vol. 33, no. 14, pp. 1-17 ( 11 )   2020.7

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    Publishing type：Research paper (scientific journal)  

    DOI： 10.1002/dac.4430

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  • System design for traveling maintenance in wide-area telecommunication networks Reviewed

    K. Hirata, H. Yamamoto, S. Kamamura, T. Oka, T. Uematsu, H. Maeda, M. Yamamoto

    IEICE Transactions on Communications   vol. E-103B, no.4, pp. 363-374   2020.4

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  • Implementation of multiple routing configurations on software-defined networks with P4

    Kouji Hirata, Takuji Tachibana

    2019 Asia-Pacific Signal and Information Processing Association Annual Summit and Conference, APSIPA ASC 2019   13 - 16   2019.11

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    Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Institute of Electrical and Electronics Engineers Inc.  

    In order to maintain high availability of communication networks, we should recover failures immediately after the failures occur. As one of techniques achieving such fast failure recovery, multiple routing configurations (MRC) have been proposed. In MRC, multiple backup routing configurations are prepared in advance to fast repair a single link/node failure. When a failure occurs during data transmission using a normal routing configuration, MRC changes the routing configuration to another routing configuration that does not use the failed point. Thus, MRC can realize fast recovery within few tens of milliseconds and continue the data transmission. In this paper, we implement MRC on software-defined networks with P4 (Programming Protocol-independent Packet Processeros). P4 is a programming language that enables us to define the behavior of the data plane of network equipment. We examine the MRC implementation, using Mininet.

    DOI： 10.1109/APSIPAASC47483.2019.9023230

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  • Characteristics of selective and tunable wavelength converters using quasi-phase matched lithium niobate waveguide devices with dual pump configuration Reviewed

    Y. Fukuchi, K. Hirata, J. Maeda

    Optics Communications   vol. 432, pp. 71-78   2019.2

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  • Residual Capacity-Aware Virtual Machine Assignment for Reducing Network Loads in Multi-tenant Data Center Networks.

    Tomotaka Kimura, Takaya Suzuki, Kouji Hirata, Masahiro Muraguchi

    J. Network Syst. Manage.   27 ( 4 )   949 - 971   2019

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    Publishing type：Research paper (scientific journal)  

    DOI： 10.1007/s10922-019-09492-1

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  • Stochastic modeling of self-evolving botnets with vulnerability discovery

    Kudo, Takanori, Kimura, Tomotaka, Inoue, Yoshiaki, Aman, Hirohisa, Hirata, Kouji

    COMPUTER COMMUNICATIONS   124   101 - 110   2018.6

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER  

    Machine learning techniques have been actively studied and achieved significant performance improvements in various kinds of tasks. While we benefit from such techniques in many ways, they can be a serious security threat to the Internet if malicious attackers become able to utilize them to discover unknown software vulnerabilities. This paper introduces a new concept of self-evolving botnets, where computing resources of infected hosts are exploited to discover unknown vulnerabilities in non-infected hosts and the botnets evolve autonomously. We provide a stochastic epidemic model for the self-evolving botnets, and show its behaviors through numerical and simulation experiments.

    DOI： 10.1016/j.comcom.2018.04.010

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  • Adaptive access-point and channel selection method using Markov approximation

    Kimura, Tomotaka, Hirata, Kouji, Muraguchi, Masahiro

    INTERNATIONAL JOURNAL OF DISTRIBUTED SENSOR NETWORKS   14 ( 2 )   2018.2

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：SAGE PUBLICATIONS INC  

    This article proposes an access-point and channel selection method for Internet of Things environments. Recently, the number of wireless nodes has increased with the growth of Internet of Things technologies. In order to accommodate traffic generated by the wireless nodes, we need to utilize densely placed wireless access-points. This article introduces a joint optimization problem of access-point and channel selection for such an environment. The proposed method deals with the optimization problem, using Markov approximation which adapts to dynamic changes in network conditions. Markov approximation is a distributed optimization framework, where a network is optimized by individual behavior of users forming a time-reversible continuous-time Markov chain. The proposed method searches optimal solution for the access-point and channel selection problem on the time-reversible continuous-time Markov chain. Simulation experiments demonstrate the effectiveness of the proposed method.

    DOI： 10.1177/1550147718761584

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  • Flow-based routing for flow entry aggregation in software-defined networking

    Koichi Yoshioka, Kouji Hirata, Miki Yamamoto

    IEICE Transactions on Communications   E101B ( 1 )   49 - 57   2018.1

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Electronics, Information and Communication, Engineers, IEICE  

    In recent years, software-defined networking (SDN), which performs centralized network management with software, has attracted much attention. Although packets are transmitted based on flow entries in SDN switches, the number of flow entries that the SDN switches can handle is limited. To overcome this difficulty, this paper proposes a flow-based routing method that performs flexible routing control with a small number of flow entries. The proposed method provides mixed integer programming. It assigns common paths to flows that can be aggregated at intermediate switches, while considering the utilization of network links. Because it is difficult for mixed integer programming to compute largescale problems, the proposed method also provides a heuristic algorithm for them. Through numerical experiments, this paper shows that the proposed method efficiently reduces both the number of flow entries and the loads of congested links.

    DOI： 10.1587/transcom.2017ITP0007

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  • Characteristics of all-optical 3R regenerators using cascaded second-order nonlinear effect in quasi-phase matched lithium niobate devices

    Yutaka Fukuchi, Tomotaka Kimura, Kouji Hirata

    OPTICAL AND QUANTUM ELECTRONICS   49 ( 9 )   2017.9

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

    We numerically show that quasi-phase matched (QPM) lithium niobate (LN) devices employing the cascaded second-order nonlinear effect of second harmonic generation (SHG) and difference frequency mixing (DFM) have all-optical decision gate characteristics. The decision gate function is realized by a parabolic transmittance for a low-power region and a limiting characteristic for a high-power region. The limiter function is attributed to the large group-velocity mismatch between the fundamental and second harmonic pulses. This operation principle differs from those of other all-optical 2R (reamplification and reshaping) or 3R (2R and retiming) regenerators that have been proposed in the past. Furthermore, we show that an initial time offset between the signal and clock pulses can improve the output signal power or the switching efficiency of the device. Based on the numerical results, we propose a method for designing all-optical 3R regenerators using the cascade of SHG and DFMin the QPM-LN devices. Following the design method, all-optical 3R operation at the bit rate of 200 Gbps can be achieved using a 1-cm-long waveguide device.

    DOI： 10.1007/s11082-017-1141-1

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  • Rational harmonic mode-locked laser using a bismuth-oxide-based highly nonlinear erbium-doped fiber Reviewed

    Yutaka Fukuchi, Kouji Hirata, Masahiro Muraguchi, Joji Maeda

    Optics Communications   383   397 - 401   2017.1

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    Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

    DOI： 10.1016/j.optcom.2016.09.039

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  • Design of low power all-optical networks with dynamic lightpath establishment Reviewed

    K. Hirata, K. Ito, Y. Fukuchi, M. Muraguchi

    IEEE/KICS Journal of Communications and Networks   vol. 18, no. 4, pp. 551-558   2016.11

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  • Fairness Improvement of Multiple-Bottleneck Flow in Data Center Networks

    Kenta Matsushima, Kouji Hirata, Miki Yamamoto

    IEICE TRANSACTIONS ON COMMUNICATIONS   E99B ( 7 )   1445 - 1454   2016.7

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    Quantized congestion notification (QCN), discussed in IEEE 802.1Qau, is one of the most promising Layer 2 congestion control methods for data center networks. Because data center networks have fundamentally symmetric structures and links are designed to have high link utilization, data center flows often pass through multiple bottleneck links. QCN reduces its transmission rate in a probabilistic manner with each congestion notification feedback reception, which might cause excessive regulation of the transmission rate in a multiple-bottleneck case because each bottleneck causes congestion feedbacks. We have already proposed QCN with bottleneck selection (QCN/BS) for multicast communications in data center networks. Although QCN/BS was originally proposed for multicast communications, it can also be applied to unicast communications with multiple bottleneck points. QCN/BS calculates the congestion level for each switch based on feedback from the switch and adjusts its transmission rate to the worst congestion level. In this paper, we preliminarily evaluate QCN/BS in unicast communications with multiple tandem bottleneck points. Our preliminary evaluation reveals that QCN/BS can resolve the excessive rate regulation problem of QCN but has new fairness problems for long-hop flows. To resolve this, we propose a new algorithm that integrates QCN/BS and our already proposed Adaptive BC_LIMIT. In Adaptive BC_LIMIT, the opportunities for rate increase are almost the same for all flows even if their transmission rates differ, enabling an accelerated convergence of fair rate allocation among flows sharing a bottleneck link. The integrated algorithm is the first congestion control mechanism that takes into account unicast flows passing through multiple tandem bottleneck points based on QCN. Furthermore, it does not require any modifications of switches used in QCN. Our simulation results show that our proposed integration of QCN/BS and Adaptive BC_LIMIT significantly mitigates the fairness problem for unicast communications with multiple bottleneck points in data center networks.

    DOI： 10.1587/transcom.2015EBP3404

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  • Dynamic lightpath establishment considering four-wave mixing for achieving low-power all-optical networks Reviewed

    K. Hirata, M. Muraguchi

    Electronics and Communications in Japan   vol. 99, no. 6, pp. 3-12   2016.5

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  • Numerical Analyses of All-Optical Retiming Switches Using Cascade of Second Harmonic Generation and Difference Frequency Mixing in Periodically Poled Lithium Niobate Waveguides

    Yutaka Fukuchi, Kouji Hirata, Joji Maeda

    IEICE TRANSACTIONS ON ELECTRONICS   E98C ( 12 )   1143 - 1149   2015.12

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    In all-optical switches using the cascade of second harmonic generation and difference frequency mixing in periodically poled lithium niobate (PPLN) waveguide devices, walk-off between the fundamental and second harmonic pulses causes crosstalk between neighboring symbols, and limits the switching performance. In this paper, we numerically study retiming characteristics of all-optical switches that employ the PPLN waveguide devices with consideration for the effects of the crosstalk and for the input timing of the data and clock pulses. We find that the time offset between the data and clock pulses can control the timing jitter of the switched output; an appropriate offset can reduce the jitter while improving the switching efficiency.

    DOI： 10.1587/transele.E98.C.1143

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  • Extra-broadband wavelength-tunable actively mode-locked short-cavity fiber ring laser using a bismuth-based highly nonlinear erbium-doped fiber

    Yutaka Fukuchi, Kouji Hirata, Hiroshi Ikeoka

    OPTICS COMMUNICATIONS   324   141 - 146   2014.8

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

    We demonstrate an ultra-wideband wavelength-tunable actively mode-locked short-cavity laser employing a 151-cm-long bismuth-based highly nonlinear erbium-doped fiber (Bi-HNL-EDF). A wavelength tuning range of 87 nm from 1533 nm to 1620 nm can be achieved because the Bi-HNL-EDF has an ultra-wide gain bandwidth. High nonlinearity of the Bi-HNL-EDF also collaborates with spectral filtering by an optical bancipass filter to suppress the supermode noise quite effectively. Total length of the fiber ring cavity is as short as 16 m. Thus, stable and clean 5.6-6.1 ps pulses with a repetition rate of 10 GHz are successfully obtained over the wavelength tuning range almost completely covering both the conventional wavelength band (1530-1565 nm) and the longer wavelength band (1565-1625 nm). The bismuth-based short-cavity fiber laser also shows good performance in the back-to-back bit-error-rate measurements, and maintains bit-error-free mode-locking operation throughout the entire wavelength tuning range. (C) 2014 Elsevier B.V. All rights reserved.

    DOI： 10.1016/j.optcom.2014.03.050

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  • 四光波混合の影響を考慮した全光ネットワーク省電力化のための光パス設定手法 Reviewed

    平田孝志, 村口正弘

    電気学会論文誌   vol. 134, no. 8, pp. 1016-1023   2014.8

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  • Wavelength-Tunable and Bandwidth-Variable Ultra-Flat Optical Frequency Comb Block Generation From a Bismuth-Based Actively Mode-Locked Fiber Laser

    Yutaka Fukuchi, Kouji Hirata, Hiroshi Ikeoka

    IEEE PHOTONICS JOURNAL   6 ( 1 )   2014.2

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

    We generate, for the first time and to the best of our knowledge, a tunable ultra-flat optical frequency comb (OFC) block from a 10-GHz bismuth-based actively mode-locked fiber laser. A bismuth-based erbium-doped fiber (Bi-EDF) with a length of 1.5 m and a bismuth-based highly nonlinear fiber (Bi-HNLF) with a length of 4.1 m are used as a gain medium and a spectral broadening device, respectively. We also employ a wavelength-tunable and bandwidth-variable optical filter for an intracavity filter. The center wavelength of the OFC output can be widely tuned from 1535 to 1585 nm because the Bi-EDF has a broadband gain profile. A spectrally broadened ultra-flat OFC is successfully generated by the self-phase modulation in the Bi-HNLF. By tuning the filter bandwidth, the 10-dB spectral width and the pulsewidth of the generated OFC can be widely varied from 0.23 to 2.4 nm and from 3 to 20.1 ps, respectively. The fiber ring cavity is as short as 17.8 m. For the entire tuning ranges, the proposed bismuth-based tunable ultra-flat OFC generator also realizes stable bit-error-free mode-locking operation.

    DOI： 10.1109/JPHOT.2013.2295469

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  • Dynamic lightpath establishment considering four wave mixing in multifiber WDM networks Reviewed

    K. Hirata, Y. Fukuchi, M. Muraguchi

    Photonic Network Communications   vol. 26, no. 2, pp. 120-130   2013.9

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  • Group replica caching scheme for optical grid networks

    Kouji Hirata, Minoru Kawahara

    Optical Switching and Networking   10 ( 3 )   223 - 232   2013

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    Language：English   Publishing type：Research paper (scientific journal)  

    This paper proposes a cache replacement scheme named group replica caching for optical grid networks. In optical grid networks, data files for job execution are replicated at multiple servers in order to distribute loads. Clients download these files via lightpaths and store them as necessary. File downloading is blocked when the corresponding lightpath cannot be established. The blocking probability of file downloading depends on location of files. The case where a file is stored in a client is ideal because blocking of lightpath establishments does not occur. However, the storage size of the client is limited. In order to efficiently use storage resources of clients, our proposed scheme focuses on the fact that clients can download files stored in surrounding servers with low blocking probability. The proposed scheme regards a group of storages of a client and its surrounding servers as one storage. In particular, they preferentially store different files. By doing so, the probability that a file is stored at the client or its surrounding servers increases. Through simulation experiments, we show that the proposed scheme improves the blocking probability of file downloading efficiently. © 2013 Elsevier Ltd.

    DOI： 10.1016/j.osn.2013.02.006

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  • Dynamic routing and wavelength assignment in multifiber WDM networks with wavelength conversion capability Reviewed

    K. Hirata, Dewiani

    Network and Communication Technologies   vol. 1, no. 2, pp. 36-47   2012.12

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  • Contention resolution considering multicast traffic in optically burst-switched WDM networks

    Kouji Hirata, Minoru Kawahara

    PHOTONIC NETWORK COMMUNICATIONS   23 ( 2 )   157 - 165   2012.4

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

    This paper proposes a contention resolution scheme considering multicast traffic in optical burst switching (OBS) networks. In OBS networks, for unicast bursts, contention can be avoided by deflection routing. However, deflection routing cannot be applied to multicast bursts because multicast bursts are transmitted along light-trees which are fixed, tree-shaped routes. Therefore, the loss probability of multicast bursts is generally high. To resolve this problem, the proposed scheme introduces an ingenious offset time assignment strategy which completely avoids contention of multicast bursts due to transmissions of unicast bursts by strategically assigning additional offset times. Furthermore, in the proposed scheme, unicast bursts avoid contention with deflection routing. Through simulation experiments, we show that the proposed scheme improves the loss probabilities of both of unicast bursts and multicast bursts.

    DOI： 10.1007/s11107-011-0346-7

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  • Dynamic routing and wavelength assignment with backward reservation in wavelength-routed multifiber WDM networks

    Dewiani, Kouji Hirata, Khamisi Kalegele, Yoshinobu Higami, Shin-ya Kobayashi

    Journal of Networks   7 ( 9 )   1441 - 1448   2012

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    Language：English   Publishing type：Research paper (scientific journal)  

    In wavelength-routed WDM networks, blocking probability of lightpath establishments is generally high due to coarse granularity and wavelength continuity constraint. Therefore, blocking of lightpath establishments is one of crucial issues which must be resolved. Multifiber environments reduce blocking probability of lightpath establishments because each link consists of multiple fibers and multifiber links can be viewed as limited-range wavelength conversion. Blocking probability can be further reduced by an appropriate routing and wavelength assignment (RWA) scheme. This paper proposes a dynamic RWA scheme using signaling of backward reservation for wavelength-routed multifiber WDM networks. In the proposed scheme, information on link state is collected by signaling of backward reservation along multiple routes between a sender node and a receiver node whenever a new lightpath-setup request arrives. Then the proposed scheme selects a combination of a route and a wavelength at the receiver node based on the collected information in such a way that it avoids the generation of bottleneck links and the depletion of a specific wavelength. Through simulation experiments, we show that the proposed scheme efficiently reduces blocking probability of lightpath establishments in multifiber WDM networks. © 2012 ACADEMY PUBLISHER.

    DOI： 10.4304/jnw.7.9.1441-1448

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  • RE-OLSR: Residual energy-based OLSR protocol in mobile ad hoc networks Reviewed

    Wardi, K. Hirata, Y. Higami, S. Kobayashi

    International Journal of Multimedia Technology   vol. 1, no. 2, pp. 93-97   2011.12

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  • Parallel and multi-wavelength downloading in optical grid networks Reviewed

    K. Hirata, M. Kawahara

    Photonic Network Communications   vol. 22, no. 3, pp. 245-253   2011.6

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  • Replica selection and downloading based on wavelength availability in λ-grid networks

    Kouji Hirata, Khamisi Kalegele, Yoshinobu Higami, Shin-ya Kobayashi

    Journal of Communications   5 ( 9 )   692 - 702   2010.10

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    Language：English   Publishing type：Research paper (scientific journal)  

    This paper proposes a replica selection and downloading scheme in λ-grid networks. In λ grid networks, in order to distribute loads and achieve high performance computing, a large amount of data is replicated on storage servers as files, and clients download these replicas. To download replicas efficiently, an appropriate replica selection scheme which avoids wavelength contention is required because λ-grid networks employ optical networking. The proposed scheme provides Replica Selection based on Wavelength Availability (RSWA). According to RSWA, a replica is selected based on wavelength availability collected by backward reservation. Furthermore, to suppress blocking probability of download attempts and improve downloading time of replicas, the proposed scheme introduces multiwavelength downloading, which determines the number of wavelengths used for each downloading based on wavelength availability. Through simulation experiments, we show that the proposed scheme can reduce blocking probability of download attempts and improve average downloading time efficiently. © 2010 ACADEMY PUBLISHER.

    DOI： 10.4304/jcm.5.9.692-702

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  • Three-Domain Burst Scheduling in Optically Burst-Switched WDM Networks

    Kouji Hirata, Takahiro Matsuda, Tetsuya Takine

    JOURNAL OF OPTICAL COMMUNICATIONS AND NETWORKING   2 ( 6 )   332 - 343   2010.6

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：OPTICAL SOC AMER  

    This paper proposes three-domain (3-D) burst scheduling in optically burst-switched WDM networks. This scheme completely eliminates contention at intermediate core nodes by combining contention avoidance schemes in the space, wavelength, and time domains. In the space and wavelength domains, the proposed scheme constructs multiple fixed, tree-shaped routes for burst transmission called lambda-trees, each of which is assigned a wavelength. Note that lambda-trees with the same wavelength do not share any links, and therefore the proposed scheme provides contention-free transmission among bursts transmitted on different lambda-trees. Furthermore, in the time domain, the proposed scheme introduces an ingenious offset time assignment scheme named burst grooming, which eliminates contention on each lambda-tree. As a result, contention at intermediate core nodes is completely eliminated because each ingress node schedules incoming bursts onto lambda-trees with burst grooming. We provide lambda-tree construction and burst scheduling algorithms, which aim to minimize the overall burst loss probability. Extensive simulation experiments show that the proposed scheme improves the overall burst loss performance dramatically without wavelength conversion.

    DOI： 10.1364/JOCN.2.000332

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  • Dynamic parallel downloading with network coding in λ-grid networks Reviewed

    K. Hirata, K. Kalegele, Y. Higami, S. Kobayashi

    Journal of Communications   vol. 5, no. 5, pp. 425-435   2010.2

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  • An effective filtering method based on occurrence rates and consistency in personalized information delivery systems Reviewed

    K. Matsumura, K. Hirata, Y. Higami, S. Kobayashi

    Polish Journal of Environmental Studies   vol. 18, no. 4A, pp. 54-58   2009.10

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  • Multiplexing scheme with distributed processing in external grids Reviewed

    K. Sugimoto, K. Hirata, Y. Higami, S. Kobayashi

    Polish Journal of Environmental Studies   vol. 18, no. 4A, pp. 50-53   2009.10

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  • Information filtering method using diversity among languages for personalized information delivery systems Reviewed

    T. Ooka, K. Hirata, Y. Higami, S. Kobayashi

    Polish Journal of Environmental Studies   vol. 18, no. 4A, pp. 67-71   2009.10

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  • Contention-free λ-planes in optically burst-switched WDM networks Reviewed

    K. Hirata, T. Matsuda, T. Takine

    IEICE Transactions on Communications   vol. E90-B, no. 9, pp. 2524-2531   2007.9

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  • Dynamic burst discarding scheme for deflection routing in optical burst switching networks

    Kouji Hirata, Takahiro Matsuda, Tetsuya Takine

    Optical Switching and Networking   4 ( 2 )   106 - 120   2007.6

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    Language：English   Publishing type：Research paper (scientific journal)  

    This paper proposes a dynamic burst discarding scheme for deflection routing in optical burst switching networks. In general, deflection routing is effective in lightly loaded situations, whereas it has a contrary effect in congested networks because deflected bursts accelerate network congestion. Thus deflection routing should be employed in lightly loaded networks. Incoming traffic, however, varies in time and location, so that temporal and/or local congestion cannot be avoided. Our proposed scheme resolves this problem in the following way. Each node autonomously detects congestion with local information, and bursts to be deflected are discarded in a probabilistic manner, based on the degree of detected congestion and the numbers of elapsed and remaining hops of those bursts. Simulation experiments show that when congestion happens temporarily, the proposed scheme reduces the burst loss probability, and it utilizes network resources efficiently when local congestion happens. © 2007 Elsevier B.V. All rights reserved.

    DOI： 10.1016/j.osn.2007.01.001

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  • Auxons: A large scale distributed storage system for semi-structured data

    Kamoliddin Mavlonov, Kouji Hirata, Yoshinobu Higami, Shin Ya Kobayashi

    RPC 2010 - 1st Russia and Pacific Conference on Computer Technology and Applications   120 - 124   2010.12

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    Auxons is a non-relational column-based distributed storage system for managing a very large amounts of semi-structured data to scale out among thousands of commodity servers, while providing high availability and high performance. In many ways Auxons is simple and flexible compare to RDBMS: to leave a complex, often-unused RDBMS features, schema free, elastic table evolving, and no pre-defined data formats (everything is string). Adding, editing and retrieving the data through a simple set of API calls. In practice this type non-relational storage systems are used for cloud services, though they typically do not support ACID transaction and with a goal of massive scaling. In this paper, we describe the design and implementation of Auxons as our solution of middleware for cloud services.

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  • Proactive Contention Avoidance Scheme with Dedicated Wavelength Assignment in Optically Burst-Switched WDM Networks Reviewed

    K. Hirata, T. Matsuda, T. Takine

    2007.7

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    Language：English  

    DOI： 10.1109/WOCN.2007.4284205

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Presentations

  • UAVネットワークにおけるアクセスポイントの配置と選択

    木村 共孝, 可香谷 昌人, 伊藤 友輔, 平田 孝志, 村口 正弘

    2020.3 

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    Event date： 2020.3

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  • ネットワーク規模を考慮したマルウェアの感染拡散予測法

    岸岡 圭太, 木村 共孝, 平田 孝志

    2020.3 

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    Event date： 2020.3

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  • 数理モデルによる将来のボットネット感染ダイナミクスの考察

    熊井 雄野, 木村 共孝, 平田 孝志

    2020.3 

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    Event date： 2020.3

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  • FLIPITゲームを用いたマルウェア感染拡散モデルの考察

    三浦 秀芳, 木村 共孝, 平田 孝志

    2020.3 

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    Event date： 2020.3

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  • エッジコンピューティング環境におけるノード/リンク障害を考慮した仮想マシン配置の検討

    上野 拓海, 平田 孝志

    2020.3 

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    Event date： 2020.3

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  • SDNにおけるTCAMの利用効率を考慮したフローエントリの割当手法

    濱田 恭平, 平田 孝志

    2020.3 

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    Event date： 2020.3

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  • エラスティック光パスネットワークにおけるコア間クロストークを考慮した静的RMLSA手法

    米田 真大, 近藤 広斗, 福地 裕, 平田 孝志

    2020.3 

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    Event date： 2020.3

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  • コンテンツ人気度の地域的な偏りを考慮したネットワーク内キャッシュ管理手法

    福島 健人, 平田 孝志

    2020.3 

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    Event date： 2020.3

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  • 畳み込みニューラルネットワークを用いた保護リンク決定法

    長澤 由利奈, 木村 共孝, 平田 孝志

    2020.1 

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    Event date： 2020.1

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  • エッジコンピューティング環境におけるサーバ配置と仮想マシン配置の同時最適化の検討

    竹田 彩夏, 木村 共孝, 平田 孝志

    2020.1 

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    Event date： 2020.1

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  • エッジコンピューティングにおけるフィードバック生成時間を考慮したキャッシング手法

    和田 優介, 伊藤 友輔, 木村 共孝, 平田 孝志, 村口 正弘

    2020.1 

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    Event date： 2020.1

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  • エッジコンピューティング環境における負荷を考慮したVM配置最適化

    南宮 翔太, 木村 共孝, 平田 孝志

    2020.1 

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    Event date： 2020.1

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  • P4を用いた複数ルーティング構成における構成切替機能の実装の検討

    平田 孝志, 橘 拓至

    2020.1 

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  • 将来のマルウェア進化に対する感染対策モデルの検討

    平田 孝志, 木村 共孝

    2019.11 

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    Event date： 2019.11

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  • Evaluation of countermeasure against future malware evolution with deterministic modeling

    Koki Shimizu, Yuya Kumai, Kimiko Motonaka, Tomotaka Kimura, Kouji Hirata

    Asia-Pacific Signal and Information Processing Association Annual Summit and Conference (APSIPA ASC 2019)  2019.11 

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    Event date： 2019.11

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  • Implementation of multiple routing configurations on software-defined networks with P4

    K. Hirata, T. Tachibana

    Asia-Pacific Signal and Information Processing Association Annual Summit and Conference (APSIPA ASC 2019)  2019.11 

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    Event date： 2019.11

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  • ネットワークスライスに対する効率的な高速障害復旧技術のP4による実装の一検討

    平田 孝志, 橘 拓至

    2019.10 

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    Event date： 2019.10

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  • CNNを用いたネットワーク可用性の推定手法

    長澤 由利奈, 木村 共孝, 工藤 隆則, 平田 孝志

    電子情報通信学会技術研究報告  2019.7 

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    Event date： 2019.7

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  • 決定論的モデルによる将来のマルウェア進化に対する感染対策の評価

    清水 浩毅, 熊井 雄野, 本仲 君子, 木村 共孝, 平田 孝志

    電子情報通信学会技術研究報告  2019.7 

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    Event date： 2019.7

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  • Malicious node detection method against message flooding attacks in aparse mobile ad-hoc networks

    T. Idezuka, T. Kimura, K. Hirata, M. Muraguchi

    the Fifteenth International Conference on Wireless and Mobile Communications (ICWMC 2019)  2019.7 

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    Event date： 2019.7

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  • Consideration of a countermeasure model against self-evolving botnets

    K. Hirata, K. Hongyo, T. Kudo, Y. Inoue, K. Hirata

    the Eleventh International Conference on Evolving Internet (INTERNET 2019)  2019.7 

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    Event date： 2019.7

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  • エッジコンピューティング環境における仮想マシン配置手法の検討

    南宮 翔太, 木村 共孝, 平田 孝志

    電気学会通信研究会  2019.6 

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    Event date： 2019.6

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  • エッジコンピューティング環境におけるエッジクラウドサーバ配置の最適化

    竹田 彩夏, 木村 共孝, 平田 孝志

    電気学会通信研究会  2019.6 

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    Event date： 2019.6

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  • NFV環境におけるネットワーク負荷低減のためのルーティング手法

    四方 航輔, 濱田 恭平, 木村 共孝, 平田 孝志

    電気学会通信研究会  2019.6 

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    Event date： 2019.6

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  • エッジコンピューティング環境における仮想マシン配置を考慮したトラフィックルーティング最適化

    上野 拓海, 木村 共孝, 平田 孝志

    電気学会通信研究会  2019.6 

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    Event date： 2019.6

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  • P4を用いた複数ルーティング構成法の実装及び評価

    平田 孝志, 橘 拓至

    電子情報通信学会NV研究会  2019.5 

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    Event date： 2019.5

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  • Trajectory estimation method using sparsely deployed anchor nodes

    T. Kimura, A. Noguchi, K. Hirata, M. Muraguchi

    IEEE International Conference on Consumer Electronics - Taiwan (IEEE ICCE-TW 2019)  2019.5 

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  • Static routing and spectrum allocation for mitigating crosstalk in multi-core fiber networks

    H. Kondo, T. Kimura, Y. Fukuchi, K. Hirata

    IEEE International Conference on Consumer Electronics - Taiwan (IEEE ICCE-TW 2019)  2019.5 

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  • Estimation method of network availability with convolutional neural networks

    Y. Nagasawa, T. Kimura, T. Kudo, K. Hirata

    IEEE International Conference on Consumer Electronics - Taiwan (IEEE ICCE-TW 2019)  2019.5 

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    Event date： 2019.5

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  • Evaluation of edge cloud server placement for edge computing environments

    A. Takeda, T. Kimura, K. Hirata

    IEEE International Conference on Consumer Electronics - Taiwan (IEEE ICCE-TW 2019)  2019.5 

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  • 疎に配置されたアンカーノードを用いた移動軌跡の推定法

    木村 共孝, 野口 晃, 平田 孝志, 村口 正弘

    電子情報通信学会技術研究報告  2019.5 

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  • Traveling maintenance system design for wide-area telecommunication networks

    K. Hirata, H. Yamamoto, S. Kamamura, T. Oka, T. Uematsu, H. Maeda, M. Yamamoto

    IEEE ComSoc International Communications Quality and Reliability Workshop (IEEE CQR 2019)  2019.4 

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    Event date： 2019.4

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  • P4を用いた複数ルーティング構成法の実装に関する検討

    橘 拓至, 平田 孝志

    電子情報通信学会総合大会  2019.3 

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    Event date： 2019.3

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  • 自律進化型ボットネットに対する感染対策モデルの検討

    本行 航希, 工藤 隆則, 木村 共孝, 井上 文彰, 平田 孝志

    電子情報通信学会技術研究報告  2019.3 

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    Event date： 2019.3

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  • 決定論的モデルによる自律進化型ボットネットの拡散挙動解析

    熊井 雄野, 本行 航希, 木村 共孝, 平田 孝志

    電子情報通信学会技術研究報告  2019.3 

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    Event date： 2019.3

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  • P4による複数ルーティング構成法の実装評価

    平田 孝志, 橘 拓至

    電子情報通信学会総合大会  2019.3 

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    Event date： 2019.3

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  • Popularity-based content cache management for in-network caching

    T. Fukushima, M. Iio, K. Hirata, M. Yamamoto

    the 33rd International Conference on Information Networking (ICOIN 2019)  2019.1 

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    Event date： 2019.1

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  • Infection dynamics of self-evolving botnets with deterministic modeling

    Y. Kumai, K. Hongyo, T. Kimura, K. Hirata

    the 33rd International Conference on Information Networking (ICOIN 2019)  2019.1 

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    Event date： 2019.1

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  • 待機型巡回保守のための保守システム設計法

    平田 孝志, 山本 宏, 鎌村 星平, 植松 芳彦, 岡 利幸, 前田 英樹, 山本 幹

    電子情報通信学会技術研究報告  2018.12 

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    Event date： 2018.12

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  • 電力消費を考慮したエラスティック光パスネットワーク設計手法

    工藤 隆則, 木村 共孝, 平田 孝志

    電子情報通信学会技術研究報告  2018.11 

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    Event date： 2018.11

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  • Prediction method of infection spreading with CNN for Self-evolving Botnets

    K. Kishioka, K. Hongyo, T. Kimura, T. Kudo, Y. Inoue, K. Hirata

    Asia-Pacific Signal and Information Processing Association Annual Summit and Conference (APSIPA ASC 2018)  2018.11 

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    Event date： 2018.11

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  • Stochastic modeling for self-evolving botnets in infection control environments

    K. Hongyo, T. Kimura, T. Kudo, Y. Inoue, K. Hirata

    the 14th Advanced International Conference on Telecommunications (AICT 2018)  2018.7 

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  • Routing and spectrum allocation method to avoid the generation of crosstalk and the blocking of lightpath establishment in multi-core fiber networks

    T. Kimura, K. Goto, K. Morita, K. Hirata, Y. Fukuchi, M. Muraguchi

    the 14th Advanced International Conference on Telecommunications (AICT 2018)  2018.7 

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    Event date： 2018.7

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  • 疎密度モバイルアドホック網におけるメッセージフラッディングの検出手法

    出塚 拓也, 木村 共孝, 平田 孝志, 村口 正弘

    電気学会通信研究会  2018.6 

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    Event date： 2018.6

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  • 受信信号強度を考慮したマルコフ近似によるアクセスポイント選択法

    可香谷 昌人, 木村 共孝, 平田 孝志, 村口 正弘

    電気学会通信研究会  2018.6 

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    Event date： 2018.6

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  • SDNにおけるTCAMキャッシュルールの置換手法

    濱田 恭平, 平田 孝志

    電気学会通信研究会  2018.6 

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    Event date： 2018.6

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  • 畳み込みニューラルネットワークを用いたインターネットトラヒックフロー分類手法

    岸岡 圭太, 工藤 隆則, 平田 孝志

    電気学会通信研究会  2018.6 

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    Event date： 2018.6

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  • 自律進化型ボットネットの決定論的モデル化

    熊井 雄野, 本行 航希, 木村 共孝, 本仲 君子, 平田 孝志

    電気学会通信研究会  2018.6 

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    Event date： 2018.6

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  • SDNにおける依存関係を考慮したTCAMキャッシュルールの置換手法

    濱田 恭平, 平田 孝志

    電子情報通信学会NV研究会  2018.5 

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    Event date： 2018.5

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  • CCAR: caching and content-aware routing for content oriented networking

    Y. Hayamizu, K. Hirata, M. Yamamoto

    IEEE ComSoc International Communications Quality and Reliability Workshop (CQR 2018)  2018.5 

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    Event date： 2018.5

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  • CNNによる自律進化型ボットネットの感染拡散予測法

    平田 孝志, 三吉 優太, 本行 航希, 工藤 隆則, 井上 文彰, 木村 共孝

    電子情報通信学会技術研究報告  2018.4 

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    Event date： 2018.4

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  • AQM with multi-queue for microburst in data center networks

    W. Morita, D. Sugahara, K. Hirata, M. Yamamoto

    the 8th International Workshop on Big Data and Cloud Performance (DCPerf'18)  2018.4 

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    Event date： 2018.4

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  • 感染抑制環境下における自律進化型ボットネットの確率論的モデル化

    本行 航希, 木村 共孝, 工藤 隆則, 井上 文彰, 平田 孝志

    電子情報通信学会技術研究報告  2018.1 

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    Event date： 2018.1

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  • インネットワークキャッシングのための分散型キャッシュ管理手法

    飯尾 将光, 平田 孝志, 山本 幹

    電子情報通信学会技術研究報告  2018.1 

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    Event date： 2018.1

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  • エラスティック光パスネットワークにおけるサービス時間を考慮した事前予約型光パス設定

    佐藤 勇樹, 木村 共孝, 平田 孝志, 村口 正弘

    電気学会通信研究会  2018.1 

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    Event date： 2018.1

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  • マルチテナント型データセンタネットワークにおける再帰的な仮想マシン再配置手法

    原田 祐輝, 木村 共孝, 平田 孝志, 村口 正弘

    電気学会通信研究会  2018.1 

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    Event date： 2018.1

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  • 間欠的接続センサネットワークにおけるアクティブ率の動的制御

    福岡 雅大, 木村 共孝, 平田 孝志, 村口 正弘

    電気学会通信研究会  2018.1 

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    Event date： 2018.1

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  • Identification of TCP congestion control algorithms with convolution neural networks

    T. Nogiwa, K. Hirata

    the 32nd International Conference on Information Networking (ICOIN 2018)  2018.1 

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    Event date： 2018.1

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  • データセンタにおけるマイクロバーストに適応したアクティブキュー管理機構の検討

    森田 亘, 菅原 大輔, 平田 孝志, 山本 幹

    電子情報通信学会技術研究報告  2018.1 

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    Event date： 2018.1

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  • クロストークを考慮したエラスティック光パスネットワーク設計

    森田 海, 平田 孝志

    電子情報通信学会技術研究報告  2018.1 

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    Event date： 2018.1

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  • Distributed cache management considering content popularity for in-network caching

    M. Iio, K. Hirata, M. Yamamoto

    the 23rd Asia-Pacific Conference on Communications (APCC 2017)  2017.12 

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    Event date： 2017.12

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  • マルチパスルーチングのための協調インネットワークキャッシング手法

    三吉 優太, 平田 孝志

    電気学会通信研究会  2017.11 

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    Event date： 2017.11

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  • 畳み込みニューラルネットワークによる画像認識を用いた輻輳制御の識別法

    野涯 貴博, 平田 孝志

    電気学会通信研究会  2017.11 

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    Event date： 2017.11

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  • マルコフ近似によるネットワーク最適化

    平田 孝志, 木村 共孝

    電子情報通信学会技術研究報告  2017.10 

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    Event date： 2017.10

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  • Collaborative in-network caching for multi-path routing

    Y. Miyoshi, T. Wada, K. Hirata

    IEEE International Conference on Consumer Electronics - Taiwan (ICCE-TW 2017)  2017.6 

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    Event date： 2017.6

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  • Node density estimation using sparsely deployed access points

    A. Noguchi, T. Kimura, Y. Inoue, K. Hirata, M. Muraguchi

    IEEE International Conference on Consumer Electronics - Taiwan (ICCE-TW 2017)  2017.6 

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    Event date： 2017.6

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  • Dynamic lightpath establishment method based on maximum spectrum utilization for elastic optical path networks

    Y. Sato, T. Kimura, K. Hirata, M. Muraguchi

    The 13th Advanced International Conference on Telecommunications (AICT 2017)  2017.6 

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    Event date： 2017.6

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  • Modeling of countermeasure against self-evolving botnets

    K. Hongyo, T. Kimura, T. Kudo, Y. Inoue, K. Hirata

    IEEE International Conference on Consumer Electronics - Taiwan (ICCE-TW 2017)  2017.6 

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    Event date： 2017.6

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  • マルコフ近似を用いたアクセスポイント選択によるスループット公平性の改善

    木村 共孝, 平田 孝志, 村口 正弘

    電子情報通信学会技術研究報告  2017.5 

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    Event date： 2017.5

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  • 巡回型保守実現のための設備設計最適化

    平田 孝志, 山本 宏, 鎌村 星平, 植松 芳彦, 前田 英樹, 山本 幹

    電子情報通信学会技術研究報告  2017.4 

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    Event date： 2017.4

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  • ニューラルネットワークを用いたTCP輻輳制御アルゴリズムの識別

    野涯 貴博, 平田 孝志, 山本 幹

    電子情報通信学会技術研究報告  2017.3 

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    Event date： 2017.3

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  • Content download method with distributed cache management

    M. Iio, K. Hirata, M. Yamamoto

    the 25th International MultiConference of Engineers and Computer Scientists (IMECS 2017)  2017.3 

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    Event date： 2017.3

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  • 自律進化型ボットネットの感染抑制に関する考察

    本行 航希, 木村 共孝, 工藤 隆則, 井上 文彰, 平田 孝志

    電子情報通信学会技術研究報告  2017.3 

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    Event date： 2017.3

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  • マルチテナント型データセンタネットワークにおける仮想マシン割り当て

    木村 共孝, 鈴木 孝也, 平田 孝志, 村口 正弘

    電子情報通信学会技術研究報告  2017.3 

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    Event date： 2017.3

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  • Data center traffic engineering using markov approximation

    K. Hirata, M. Yamamoto

    the 31st International Conference on Information Networking (ICOIN 2017)  2017.1 

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    Event date： 2017.1

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  • コンテンツ配置を考慮したコンテンツ指向ルーチングの性能評価

    速水 祐作, 平田 孝志, 山本 幹

    CQ基礎講座ワークショップ  2017.1 

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  • Dynamic spectrum allocation method for reducing crosstalk in multi-core fiber networks

    K. Morita, K. Hirata

    the 31st International Conference on Information Networking (ICOIN 2017)  2017.1 

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  • Static lightpath establishment method with multi-path routing in elastic optical networks

    M. Takezaki, K. Hirata

    the 31st International Conference on Information Networking (ICOIN 2017)  2017.1 

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  • Routing method with flow entry aggregation for software-defined networking

    K. Yoshioka, K. Hirata, M. Yamamoto

    the 31st International Conference on Information Networking (ICOIN 2017)  2017.1 

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  • マルコフ近似を用いた動的仮想マシン配置手法

    小林 卓矢, 木村 共孝, 平田 孝志

    電気学会通信研究会  2017.1 

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  • Dynamic access-point selection method using markov approximation

    T. Kimura, K. Hirata, M. Muraguchi

    the 31st International Conference on Information Networking (ICOIN 2017)  2017.1 

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  • 分散的キャッシュ管理を用いたコンテンツダウンロード手法

    飯尾 将光, 平田 孝志, 山本 幹

    電気学会通信研究会  2017.1 

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  • Performance analysis of intermittently connected sensor networks

    M. Fukuoka, T. Kimura, K. Hirata, M. Muraguchi

    2016 IEEE Region 10 International Conference (TENCON 2016)  2016.11 

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  • Tunable wavelength conversion of 40-Gbps signals using cascade of sum frequency mixing and difference frequency mixing in a periodically poled lithium niobate

    Y. Fukuchi, K. Hirata

    Photonics and Fiber Technology Conference  2016.9 

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  • Behavior analysis of self-evolving botnets

    T. Kudo, T. Kimura, Y. Inoue, H. Aman, K. Hirata

    the 2016 International Conference on Computer, Information, and Telecommunication Systems (CITS 2016)  2016.7 

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  • 自律進化型ボットネットの拡散にトポロジ構造が与える影響

    工藤 隆則, 木村 共孝, 井上 文彰, 阿萬 裕久, 平田 孝志

    電子情報通信学会技術研究報告  2016.7 

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  • データセンタネットワークにおける通信トラヒック量を考慮したVMの再配置手法

    原田 祐輝, 木村 共孝, 平田 孝志, 村口 正弘

    電気学会通信研究会  2016.6 

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  • マルチコアファイバネットワークにおけるクロストーク低減のための動的周波数割当法

    森田 海, 平田 孝志

    電気学会通信研究会  2016.6 

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  • Content-oriented probabilistic routing with measured RTT

    T. Mori, K. Hirata, M. Yamamoto

    IEEE ComSoc International Communications Quality and Reliability Workshop (CQR 2016)  2016.5 

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  • SDNにおける最大リンク利用率を考慮したフローエントリ削減手法

    吉岡 晃一, 平田 孝志, 山本 幹

    電子情報通信学会技術研究報告  2016.3 

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  • マルコフ近似によるデータセンタトラヒックエンジニアリング

    平田 孝志, 山本 幹

    電子情報通信学会技術研究報告  2016.3 

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  • 複数経路を考慮したエラスティック光パスネットワーク設計

    竹崎 正晃, 平田 孝志

    電子情報通信学会技術研究報告  2016.3 

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  • マルコフ近似を用いた動的なアクセスポイント選択手法

    木村 共孝, 平田 孝志, 村口 正弘

    電子情報通信学会技術研究報告  2016.3 

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  • 分散的情報共有によるコンテンツキャッシング手法

    奥村 尚久, 平田 孝志, 山本 幹

    電子情報通信学会総合大会  2016.3 

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  • データセンタ環境下におけるTCP間の公平性改善に関する一検討

    奥田 周平, 松嶋 健太, 平田 孝志, 山本 幹, 李 忠翰, 小口 直樹, 田中 淳

    電子情報通信学会総合大会  2016.3 

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  • コンテンツ配置を考慮したコンテンツ指向トラヒックエンジニアリングの検討

    速水 祐作, 平田 孝志, 山本 幹

    電子情報通信学会技術研究報告  2016.1 

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  • エラスティック光パスネットワークにおける残余占有時間を考慮したスペクトル割り当て手法

    佐藤 勇樹, 木村 共孝, 平田 孝志, 村口 正弘

    電気学会通信研究会  2016.1 

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  • 間欠的接続センサネットワークの性能解析

    福岡 雅大, 木村 共孝, 平田 孝志, 村口 正弘

    電気学会通信研究会  2016.1 

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  • データセンタネットワークにおける適応的VM割り当て手法

    鈴木 孝也, 木村 共孝, 平田 孝志, 村口 正弘

    電気学会通信研究会  2016.1 

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  • 自律進化するボットネットの感染拡散についての解析

    工藤 隆則, 木村 共孝, 井上 文彰, 阿萬 裕久, 平田 孝志

    電子情報通信学会技術研究報告  2015.12 

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  • Dynamic lightpath establishment for achieving low power all-optical networks

    K. Hirata, K. Ito, Y. Fukuchi, M. Muraguchi

    17th Asia-Pacific Network Operations and Management Symposium (APNOMS 2015)  2015.8 

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  • Flat Optical Frequency Comb Generation from an Actively Mode-Locked Short-Cavity Fiber Laser Using a Bismuth-Based Highly Nonlinear Erbium-Doped Fiber

    Y. Fukuchi, K. Hirata, J. Maeda

    11th Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR 2015)  2015.8 

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  • Design of all-optical networks considering power consumption and four-wave mixing

    K. Hirata, Y. Fukuchi, M. Muraguchi

    2015 International Conference on Computer, Information, and Telecommunication Systems (CITS 2015)  2015.7 

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  • Adaptive virtual machine assignment for multi-tenant data center networks

    T. Suzuki, T. Kimura, K. Hirata, M. Muraguchi

    2015 International Conference on Computer, Information, and Telecommunication Systems (CITS 2015)  2015.7 

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  • Rational harmonic mode-locked fiber ring laser using a bismuth-based highly nonlinear erbium-doped fiber

    Y. Fukuchi, K. Hirata

    Nonlinear Optics  2015.7 

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  • All-optical retiming switches using the cascaded second-order nonlinear effect in periodically poled lithium niobate devices: effects of domain length errors

    Y. Fukuchi, K. Hirata

    Nonlinear Optics  2015.7 

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  • 四光波混合の発生を抑制する省電力光ネットワーク設計

    平田 孝志, 福地 裕, 村口 正弘

    電子情報通信学会技術研究報告  2015.7 

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  • データセンタネットワークにおける通信トラヒック量を考慮したVM割り当て手法

    鈴木 孝也, 木村 共孝, 平田 孝志, 村口 正弘

    電気学会通信研究会  2015.6 

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  • 計測RTTを用いた確率的コンテンツ指向ルーチング手法

    上尾 祐太, 平田 孝志, 山本 幹

    電子情報通信学会技術研究報告  2015.3 

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  • 四光波混合の影響を考慮した省電力光ネットワーク設計

    平田 孝志, 福地 裕, 村口 正弘

    電子情報通信学会技術研究報告  2015.1 

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  • Design and control of all-optical networksconsidering power consumption and four-wave mixing

    K. Hirata

    4th Makassar International Conference on Electrical Engineering and Informatics  2014.11 

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  • 全光ネットワークにおける四光波混合と電力消費を考慮した光パス設定

    松本 智, 平田 孝志, 村口 正弘

    電気学会通信研究会，映像情報メディア学会技術報告  2014.9 

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  • LEDの周波数特性を考慮した可視光SSB伝送

    新井 雄大, 平田 孝志, 村口 正弘

    電子情報通信学会ソサイエティ大会  2013.9 

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  • エラスティック光パスネットワークにおける利用帯域幅を考慮したスペクトル割当

    小林 文雅, 平田 孝志, 村口 正弘

    電子情報通信学会ソサイエティ大会  2013.9 

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  • LEDを受光素子とする双方向可視光通信

    山本 築, 平田 孝志, 村口 正弘

    電子情報通信学会ソサイエティ大会  2013.9 

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  • Ultra-flat optical frequency comb block generation from an actively and harmonically mode-locked fiber laser using a bismuth-based erbium-doped fiber and a bismuth-based highly nonlinear fiber

    Y. Fukuchi, K. Hirata

    Nonlinear Optics  2013.6 

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  • ビスマスベース高調波モード同期ファイバレーザによる光周波数コムブロック生成

    福地 裕, 平田 孝志

    電子情報通信学会技術研究報告  2013.5 

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  • Dynamic routing and wavelength assignment in multifiber WDM networks with sparse wavelength conversion

    Dewiani, K. Hirata, Y. Higami, S. Kobayashi

    the 3rd International Conference on ICT Convergence (ICTC 2012)  2012.9 

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  • Replica caching scheme according to status of neighboring nodes in optical grid networks

    K. Hirata, M. Kawahara

    the 2nd IFIP International Conference on Network of the Future (NoF 2011)  2011.10 

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  • Dynamic routing and wavelength assignment scheme using signaling of backward reservation in multifiber WDM networks

    Dewiani, K. Hirata, Y. Higami, S. Kobayashi

    the 2nd International Conference on ICT Convergence (ICTC 2011)  2011.9 

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  • Residual energy-based OLSR in mobile ad hoc networks

    Wardi, K. Hirata, Y. Higami, S. Kobayashi

    the 2nd International Conference on Multimedia Technology (ICMT 2011)  2011.7 

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  • Wavelength selection based on wavelength availability in multi-fiber WDM networks

    Dewiani, K. Hirata, Y. Higami, S. Kobayashi

    the 2nd International Conference on Multimedia Technology (ICMT 2011)  2011.7 

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  • Replica selection for parallel and multi-wavelength downloading in optical grid networks

    K. Hirata, M. Kawahara

    the 4th Workshop on Network Control and Optimization (NET-COOP 2010)  2010.11 

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  • Optimistic processing protocol for multiplexing in external PC grids

    A. Funo, K. Hirata, Y. Higami, S. Kobayashi

    the 17th International Multi-Conference on Advanced Computer Systems (ACS 2010)  2010.9 

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  • Energy aware MPR selection mechanism in OLSR-based mobile ad hoc networks

    Wardi, K. Hirata, Y. Higami, S. Kobayashi

    the 17th International Multi-Conference on Advanced Computer Systems (ACS 2010)  2010.9 

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  • An effective dynamic parallel downloading scheme with network coding in λ-grid networks

    K. Hirata, Y. Higami, S. Kobayashi

    the 1st Asian Himalayas International Conference on Internet (AH-ICI2009)  2009.11 

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  • An Effective Filtering Method Based on Occurrence Rates and Consistency in Personalized Information Delivery Systems

    K. Matsumura, K. Hirata, Y. Higami, S. Kobayashi

    the 16th International Multi-Conference on Advanced Computer Systems (ACS 2009)  2009.10 

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  • Multiplexing Scheme with Distributed Processing in External Grids

    K. Sugimoto, K. Hirata, Y. Higami, S. Kobayashi

    the 16th International Multi-Conference on Advanced Computer Systems (ACS 2009)  2009.10 

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  • Information Filtering Method Using Diversity among Languages for Personalized Information Delivery Systems

    T. Ooka, K. Hirata, Y. Higami, S. Kobayashi

    the 16th International Multi-Conference on Advanced Computer Systems (ACS 2009)  2009.10 

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  • Consideration of an appropriate program segment size on method of concealing purposes of processing

    S. Takasuka, K. Hirata, Y. Higami, S. Kobayashi

    the 15th International Multi-Conference on Advanced Computer Systems (ACS 2008)  2008.10 

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  • Consideration of characteristics of programs for concealing purpose of processing in distributed computing systems

    K. Himeda, K. Hirata, Y. Higami, S. Kobayashi

    the 15th International Multi-Conference on Advanced Computer Systems (ACS 2008)  2008.10 

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  • The detection of falsification with check codes in external grid

    H. Miyaoka, K. Hirata, Y. Higami, S. Kobayashi

    the 15th International Multi-Conference on Advanced Computer Systems (ACS 2008)  2008.10 

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  • Proactive contention avoidance scheme with dedicated wavelength assignment in optically burst-switched WDM networks

    K. Hirata, T. Matsuda, T. Takine

    the 4th IEEE and IFIP International Conference on Wireless and Optical Communications Networks (WOCN 2007)  2007.7 

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  • Contention-free λ-planes in optically burst switched WDM networks

    K. Hirata, T. Matsuda, T. Takine

    IEEE Global Telecommunications Conference (GLOBECOM)  2006.11 

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  • Optimization of UAV placement with task offloading for UAV-based edge computing systems

    R. Kaneko, H. Miura, T. Kimura, K. Hirata

    2023.7 

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  • Node-based epidemic modeling for countermeasure strategies against future malware evolution

    Y. Hazama, H. Miura, T. Kimura, K. Hirata

    2023.7 

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  • Content prefetching method to utilize reinforcement learning-based routing for in-network caching

    I. Tayuki, G. Tabei, K. Hirata

    2023.7 

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  • エッジコンピューティング環境におけるQuantum-Inspired Evolutionary Algorithmを用いたエッジサーバの配置手法

    花岡 昂佑, 田部井 元, 平田 孝志

    2023.1 

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  • ドローンネットワークにおける連結性とエネルギー消費を考慮したドローン配置

    大隅 博文, 木村 共孝, 平田 孝志, 程 俊

    2023.1 

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  • 劣通信環境下における区画を考慮した微分方程式によるマルウェア拡散挙動解析の検討

    虻川 翔哉, 三浦 秀芳, 木村 共孝, 平田 孝志

    2023.1 

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  • ホストの隣接関係を考慮したマルウェア感染拡散対策モデルの考察

    狭間 雄斗, 三浦 秀芳, 木村 共孝, 平田 孝志

    2023.1 

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  • ネットワークスライシング環境における負荷分散のための障害復旧経路の設計

    三杉 彪流, 三浦 秀芳, 平田 孝志, 橘 拓至

    2023.1 

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  • EONにおけるコア間クロストークと周波数利用効率を考慮した静的RMLSA手法

    岡田 衛人, 福地 裕, 平田 孝志

    2023.1 

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  • エッジコンピューティングにおけるコンテンツ生成時間を考慮したジョブスケジューリング

    大隅 博文, 伊藤 友輔, 木村 共孝, 平田 孝志, 程 俊

    2022.11 

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  • Modeling of malware diffusion with mobile devices in intermittently connected networks

    H. Miura, T. Kimura, K. Hirata

    2022.11 

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  • 劣通信環境におけるモビリティを考慮したマルウェア感染拡散モデルの考察

    三浦 秀芳, 虻川 翔哉, 木村 共孝, 平田 孝志

    2022.10 

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  • P4を用いた複数ルーティング構成における障害及び復旧通知機能の実装

    加重 健太郎, 三浦 秀芳, 平田 孝志, 橘 拓至

    2021.1 

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  • GCNを使用したリスク推定によるマルウェア感染拡大の予測法

    宇野 克紀, 木村 共孝, 平田 孝志

    2021.1 

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  • エッジコンピューティング環境におけるSA法を用いたサーバ配置と仮想マシン割り当ての同時最適化の検討

    竹田 彩香, 木村 共孝, 平田 孝志

    2021.1 

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  • ネットワーク上の進化ゲームを用いたマルウェア感染拡散対策モデルの検討

    三浦 秀芳, 木村 共孝, 平田 孝志

    2021.1 

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  • エラスティック光パスネットワークに対する仮想ネットワーク埋め込みにおける資源利用の最適化

    吉村 勇樹, 平田 孝志

    2021.1 

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  • マルチコアファイバネットワークにおけるクロストーク制限下の経路選択及び周波数割当手法

    近藤 広斗, 福地 裕, 平田 孝志

    2021.1 

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  • 畳み込みニューラルネットワークを用いたリンク可用性推定法

    長澤 由利奈, 木村 共孝, 平田 孝志

    2021.1 

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  • ブロックチェーンに対するマルウェアを用いたシビル攻撃モデルの検討

    花輪 拓海, 平田 孝志

    2021.1 

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  • NFV環境におけるネットワーク負荷低減のためのVNF配置手法の検討

    四方 航輔, 平田 孝志

    2021.1 

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  • ドローンネットワークにおける連結性を考慮した最適ドローン配置

    大隅 博文, 木村 共孝, 平田 孝志, 程 俊

    2021.1 

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  • Optimization of virtual machine placement for balancing network and server load in edge computing environments

    S. Nangu, T. Kimura, K. Hirata

    2020.12 

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  • Implementation of a configuration switching system for multiple routing configurations with P4

    K. Hirata, T. Tachibana

    2020.12 

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  • Joint optimization of edge server and virtual machine placement in edge computing environments

    A. Takeda, T. Kimura, K. Hirata

    2020.12 

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  • Prediction method of malware infection spreading considering network scale

    Y. Nagasawa, K. Kishioka, T. Kimura, K. Hirata

    2020.12 

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  • Design of reliable and secure service-oriented network slicing with P4

    K. Hirata, T. Kawakami, T. Tachibana

    2020.11 

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  • Characteristics of a 40-GHz all-optical switch using cascaded nonlinearities in a periodically poled lithium niobate waveguide

    Y. Fukuchi, K. Hirata

    2020.10 

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  • P4向け高速障害復旧技術のルーティングテーブル生成処理の一検討

    橘 拓至, 平田 孝志

    2020.10 

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  • P4を用いた高速障害復旧のための障害検知技術の実装

    平田 孝志, 橘 拓至

    2020.10 

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  • Estimation method of malware infection spreading with graph convolutional networks

    K. Uno, T. Kimura, K. Hirata

    2020.9 

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  • Modeling of malware diffusion with the FLIPIT game

    H. Miura, T. Kimura, K. Hirata

    2020.9 

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  • Prioritization method of link protection with convolutional neural networks

    Y. Nagasawa, T. Kimura, K. Hirata

    2020.9 

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  • A caching scheme based on popularity and generation time of feedback information in edge computing

    Y. Ito, Y. Wada, T. Kimura, K. Hirata, M. Muraguchi

    2020.9 

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Research Projects

  • 高品質・高信頼な省電力ネットワークシステム最適設計の確立

    Grant number：21K11857  2021.4 - 2024.3

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    平田 孝志, 伊藤 友輔, 木村 共孝

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    Grant amount：\4160000 （ Direct Cost: \3200000 、 Indirect Cost：\960000 ）

    現在，5G・AI・IoT等の新たなサービスが展開している．また，インターネットの発展に伴い，エッジコンピューティング，ネットワークスライシングといった新たなネットワーク運用技術が展開されようとしている．急速に多様化，進化するサービスを高品質に提供するためには，これらのネットワーク運用技術と光無線融合ネットワーク基盤のサービスに応じた統合運用が必要不可欠である．また，再生可能エネルギーの促進に代表されるように，情報ネットワークの省電力化は重要な課題であり，さらには，高信頼なネットワークサービスの提供のためにはネットワーク機器の故障に対する十分な備えも必要となる．このような背景のもと，本研究課題においては，将来の高度情報通信社会を支える重要な構成要素となる高品質・高信頼な省電力ネットワークシステム最適設計の確立を目的として研究を遂行してきた．
    2021年度においては，ネットワーク運用技術として，エッジコンピューティング技術，ネットワークスライシング技術，ネットワーク内キャッシュ技術等に着目して，それらの最適設計を行った．具体的には，エッジコンピューティング環境においては，ジョブスケジューリングの提案，データキャッシュ手法の提案等を行った．また，ネットワークスライシング技術については，障害発生時の通信を保証するためのスライス設計手法の提案を行った．ネットワーク内キャッシュ技術については，ネットワーク内にキャッシュされたコンテンツを効率的にダウンロードするためのルーティング手法の提案を行った．さらにはネットワーク基盤設計として，ドローンネットワークを想定したスケジューリング手法の提案を行った．これらの研究成果については，国内研究会において発表している．また，その成果の一部を英文論文誌に投稿中であり，国際会議においても発表する予定である．

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  • 非線形光学効果と電気光学効果を用いた光電融合コヒーレントシリアルパラレル信号処理

    Grant number：21K04067  2021.4 - 2024.3

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    福地 裕, 宮内 亮一, 前田 譲治, 平田 孝志, 木村 共孝

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    Grant amount：\4160000 （ Direct Cost: \3200000 、 Indirect Cost：\960000 ）

    ブロードバンドインターネットを基軸とする高度情報化社会では、バックボーン光ネットワークに近い将来エクサビット毎秒級の超大容量性が要求される。当該システム構築のため、ディジタルコヒーレント光通信システムの研究開発が2000年代から活発化しており、ネットワークの高度化には超高速広帯域で高機能な中継ノードが必須となる。
    本研究課題では、理論と実験の両面から、分極反転周期変調擬似位相整合ニオブ酸リチウムアレイ光導波路に電圧制御機能を搭載した光-電気ハイブリッド信号処理デバイスを創出する。当該素子の結晶・構造パラメータを自在に制御することにより、高次の非線形光学効果に基づく光段コヒーレントシリアル-パラレル信号処理と、電気光学効果に基づく電気段シンセサイジングを同時に実現する。光子と電子に秘めた普遍的特質を活かし合い、これらの巧みな合成動作に基づく先進信号処理技術を開拓し、超高速広帯域でスマートなコヒーレントノードの実現を目指す。
    初年度の令和3年度は、考案デバイスを用いた各種光-電気ハイブリッド信号処理に関する数値解析を行った。具体的には、研究代表者と研究分担者が役割分担して、結晶・構造パラメータや各種の入力光と電圧信号等の最適化を行い、デバイスの試作や各種実験に備えた。本解析は、超多値変調信号に対する複雑大規模な処理にも対応できるよう、分極反転周期が光の伝搬方向に離散的多段階に変化する場合と、非周期・チャープ・任意変調等の連続的に変化する場合を対象とした。また、単一結晶中で高度のパラレル処理にも対応できるよう、光導波路をアレイ化したモデルも考えた。即ち、当該デバイスモデルは、時間、周波数、位相、空間の全軸上の信号処理を包含するようにした。

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  • Resource Adjustment and Failure Recovery Techniques with High Efficient In-band Network Telemetry and Machine Learning for Network Slices

    Grant number：20H04173  2020.4 - 2023.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

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    Grant amount：\17290000 （ Direct Cost: \13300000 、 Indirect Cost：\3990000 ）

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  • 機械学習を悪用したサイバー攻撃に対抗するネットワークシステムの研究開発

    Grant number：20H04184  2020.4 - 2023.3

    日本学術振興会  科学研究費助成事業  基盤研究(B)

    木村 共孝, 平田 孝志, 井上 文彰, 阿萬 裕久, 桂井 麻里衣, 平栗 健史

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    Grant amount：\17940000 （ Direct Cost: \13800000 、 Indirect Cost：\4140000 ）

    近年，パソコンやスマートフォンの普及に伴い，SNS，ブログ，電子商品取引など，さまざまなオンラインサービスが提供され，情報通信技術が社会経済活動に不可欠な基盤となっている．近い将来，機械学習を悪用したサイバー攻撃が出現し，その被害が爆発的に増加することが懸念されている．さらに，世間に知られていないゼロデイ脆弱性を機械学習により発見し，その脆弱性を突くことで感染を拡大させるマルウェアの出現も示唆されている．このように機械学習は日々急速に進歩しつづけており，機械学習を悪用したサイバー攻撃は今後，計り知れない脅威になり得る．将来のサイバー攻撃の脅威に対抗するにはユーザ端末やゲートウェイのみではなく，ネットワーク内部においても対抗策を講じた多重防御の確立が必要である．2020年度は「サイバー攻撃の数理モデル化」と「ネットワーク内部での対抗策」に取り組んだ．「サイバー攻撃の数理モデル化」では，サイバー攻撃の一つである自律進化型ボットネットの挙動をモデル化し，微分方程式を用いて，感染の広がりを近似的に得られる決定論的な手法を提案した．さらに，「ネットワーク内部での対抗策」では，DoS (Denial of Service) 攻撃の対抗策としてアントコロニー最適化アルゴリズムを用いたスループット抑制制御方式を提案し，シミュレーション実験により，DoS 攻撃を緩和できることを示した．また，深層学習を用いたフィッシング検知システムについても検討を行い，深層学習を用いることで，フィッシング攻撃の検知をネットワークの内部で行えることを示した．これらの研究成果は英文論文誌，国際会議，国内研究会などで多くの発表を行なっている．

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  • Development of a methodology for estimating nursing workload

    Grant number：18K10189  2018.4 - 2022.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    Ishii Atsue

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    Grant amount：\4420000 （ Direct Cost: \3400000 、 Indirect Cost：\1020000 ）

    The purpose of this study was to establish a method for measuring and accumulating workload data with a light burden, and to construct a methodology for estimating appropriate nursing staffing using this data. We also examined a mathematical methodology for identifying the relationship between the large amount of information accumulated. From the middle of the research period, data collection at practice sites became impossible due to the spread of coronavirus infection, so the research was conducted with some changes in the weight of the research plan. As a result, we established a location search system for nurses using beacons for automatic data acquisition, and confirmed the possibility of analyzing the acquired data. In addition, a mathematical methodology was established as a basis for workload analysis.

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  • Design of optical-wireless fusion networks with future networking technologies

    Grant number：18K11282  2018.4 - 2022.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    Hirata Kouji

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    Grant amount：\4420000 （ Direct Cost: \3400000 、 Indirect Cost：\1020000 ）

    This research aims at establishing a new network design approach that adopts future networking technologies as upper layer technologies while using optical-wireless fusion networks as lower layer networks. As the lower layer architectures, we proposed optimal network design methods focusing on routing and spectrum allocation problems in optical networks. Furthermore, we provided optimal network design methods for wireless networks such as intermittently connected sensor networks. As the upper layer technologies, we provided optimal design for edge computing environments. Moreover, we proposed routing algorithms for efficiently utilizing in-network caching. In this research, we showed the effectiveness of our network design through simulation and numerical experiments.

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  • Design of new generation networks combining all-optical networking and future networking technologies

    Grant number：15K15988  2015.4 - 2018.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Young Scientists (B)

    Hirata Kouji

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    Grant amount：\3510000 （ Direct Cost: \2700000 、 Indirect Cost：\810000 ）

    This research aims at establishing a new network design approach that adopts future networking technologies such as content-centric networking and software-defined networking (SDN) as upper layer technologies while using all-optical networks as lower layer networks. As the upper layer technologies, we proposed network design methods including content allocation and caching methods for the content-centric networking. Also, we proposed network design considering flow entry constraints for SDN. Furthermore, as the lower layer architectures, we focused on elastic optical path networks and designed them from multiple perspectives. In this research, we showed the effectiveness of our network design through simulation and numerical experiments.

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  • All-optical and coherent signal processing employing higher order nonlinear effects in aperiodically poled lithium niobate devices

    Grant number：15K06085  2015.4 - 2018.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    FUKUCHI Yutaka, MAEDA Joji, HIRATA Kouji

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    Grant amount：\4420000 （ Direct Cost: \3400000 、 Indirect Cost：\1020000 ）

    In this research, we study ultra-fast, extra-broadband, high-functional, and coherent all-optical signal processing circuits employing the higher order nonlinear effects in aperiodically poled lithium niobate waveguide devices. Through the numerical analyses, fundamental experiments, experimental demonstrations, and the system experiments, we both numerically and experimentally show the possibilities of such all-optical and coherent signal processing applications.

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  • New Traffic Engineering Methods for High-Speed Data Center Networks

    Grant number：26540039  2014.4 - 2017.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Challenging Exploratory Research

    Yamamoto Miki

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    Grant amount：\3510000 （ Direct Cost: \2700000 、 Indirect Cost：\810000 ）

    Datacenter networks have quite different requirements from the current wide area Internet. In this study, we try to develop new traffic engineering methods suitable for data center networks from the following 3 aspects, 1) congestion control enabling traffic distribution in time dimension, 2) traffic engineering distributing traffic in space dimension, and 3) optical network design. As our research results of this study, we develop several end-to-end new congestion control methods realizing fair share of bottleneck links in data center networks, new switch-assisted approach congestion control methods. And we develop a new traffic engineering method of distributed approach which dynamically controls traffic volumes according to dynamic traffic change in data center. We also develop optical path design method for data center networks which minimizes traffic volume on the bottleneck link.

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  • Empirical Study on Merits and Demerits of Comments Toward Software Quality

    Grant number：25330083  2013.4 - 2016.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    Aman Hirohisa, AMASAKI Sousuke, HIRATA Kouji

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    Grant amount：\4810000 （ Direct Cost: \3700000 、 Indirect Cost：\1110000 ）

    This study performed data collections and analyses focusing on the comments written in source files. Comments usually help in comprehending the programs. However, comments can also be added to mask poor readabilities of complicated programs.
    The results of this study quantitatively showed that comments written inside method (function) bodies are likely to be related to the fault-proneness in those methods (functions). This finding would be useful in enhancing the code reviewing by narrowing suspicious parts to be checked.

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  • Dynamic control technique for optical networks considering physical layer impairment

    Grant number：23700085  2011 - 2013

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Young Scientists (B)

    HIRATA KOUJI

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    Grant amount：\3380000 （ Direct Cost: \2600000 、 Indirect Cost：\780000 ）

    This research aims to establish a dynamic control technique for optical networks considering physical layer impairment. In optical networks, data are transmitted via lightpaths which are routes with dedicated wavelengths. It is very important to reduce blocking probability of lightpath establishment in the design of optical networks. Furthermore, we should consider the impact of physical layer impairment. In this research, we construct high-quality optical network environments by proposing some schemes which efficiently avoid blocking of lightpath establishment and physical layer impairment.

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  • How to make open GRID computing reliable

    Grant number：22500060  2010 - 2012

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    KOBAYASHI Shinya, HIRATA Kouji

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    Grant amount：\4290000 （ Direct Cost: \3300000 、 Indirect Cost：\990000 ）

    External GRID is a collection of many computers that belong to different owner respectively, we are afraid that computer’s owner is a bad guy,and he steals secret of program and return incorrect result. Our research’s aim is to develop new technology that achieves concealing the purpose of Program, and guaranteeing exact processing. Dummy code insertion is one of techniques against malicious analysis. There are various sorts of dummy code insertion procedures. We have implemented one sort of dummy code insertion, moreover inspected it from analyzer’s viewpoint. We got a key to improve dummy code insertion. The second outcome is experimental result showing that multiple executions is effective for not only high reliability of execution results but also high performance. Multiple execution requires several computers to process same task. After getting the results, true result can be decided by majority. We showed that higher multiplicity achieves higher reliability. Moreover, we introduced advanced processing technique to multiple executions. Under multiple executions, each computer finished its task at different time. Majority vote may be decided when over-half of computers have finished. If there are few malicious computer, we can usually win a bet that is the first result is correct. This means that we can start the next step after getting the first result. This technique is named advance processing. We indicated advanced processing achieves high performance.

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  • Development of high performance optical grid environments using characteristics of optical networks

    Grant number：20800039  2008 - 2009

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Young Scientists (Start-up)

    HIRATA Kouji

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    Grant amount：\2912000 （ Direct Cost: \2240000 、 Indirect Cost：\672000 ）

    This research aims to develop high performance optical grid environments using characteristics of optical networks. In optical networks, wavelength contention often occurs. The wavelength contention is one of the most serious issues to be resolved in not only optical networks but also optical girds. In this research, we propose some schemes to efficiently avoid wavelength contention. Through simulation experiments, we show that our proposed schemes enhance performance of optical grids by avoiding wavelength contention.

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  • オープングリッドコンピューティングにおけるセキュアプロセッシング技術の開発

    Grant number：19650012  2007 - 2008

    日本学術振興会  科学研究費助成事業  萌芽研究

    小林 真也, 平田 孝志

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    Grant amount：\3300000 （ Direct Cost: \3300000 ）

    (1)「処理の隠蔽」アルゴリズムの改善
    これまで,処理対象となるプログラムを分割し,ダミーコードと共に再構成することで,グリッドを構成するコンピュータに元のプログラムの処理や目的を隠蔽するアルゴリズムの提案を行ってきた.しかし,プログラム断片から得られる結果を収集し,次の処理コンピュータに分配する処理を信頼できるコンピュータで行うと,負荷の集中が起こってしまう.そこで,結果の受け渡しをグリッドを構成するコンピュータに行わせる一方で,複数のコンピュータを経由させることで,プログラム断片間の繋がりをわかりにくくする方法を提案した.また,提案方法に対して数学的な解析を行い,その信頼性について定量的評価を行い.実用性が高いことを示した.
    (2)「委託に対する信用性確保」技術の改善
    不正な改ざんや不正処理に対する有効な対策として,同じ処理を複数のコンピュータで行う多重化がある.エクスターナルグリッドは,インターネット上の多数のコンピュータで構成されるため,多重化による資源の消費は問題とならないが,改ざんや不正処理の検出を行うための多数決処理に伴う負荷の集中が問題となる.そこで,多数決処理もグリッドを構成するコンピュータに行わせる方法の提案を行った.
    提案方法では,同一の処理結果をもたらす複数のコンピュータとその結果を受け取る複数のコンピュータ間で,多対多の関係で,結果の受け渡しを行う.そして,結果を受け取る側で多数決処理を行い,改ざんや不正処理を検出する.この方法では,多数決処理が分散的,かつ並列的に行われる為に,負荷の集中を避けることができ,さらには高い信頼性も確保できる.また,数学的手法で,その信頼性を定量的に評価した.なお,その成果は,2009年10月開催のInternational Multi-Conference on Advanced Computer Systemsで発表の予定である.

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